Spring Boot Example Understanding

I am using Spring Boot for reading and writing into CSV file but I uanble to understand @Bean tag. Why we are using this tag for processing or writing.

For example :

@Bean
    public Step step1() {
        return stepBuilderFactory.get("step1")
                .<Person, Person> chunk(10)
                .reader(reader())
                .processor(processor())
                .writer(writer())
                .build();
    }

I also have another question why we are passing step1 within get method?